First off, I'd like to build a pair of 2-way rears to complement my DIY sub (Adire Shiva) and mains (Tannoy M4s); it would be even cooler if I could use them as standalone bookshelf speakers someday. I've narrowed it down to 2 choices (both with problems), and I'd like to know if anyone has any advice/answers.

Choice 2: Dayton 2-way bookshelfhttp://www.partsexpress.com/projects...ayton2way.html
Uses Dayton drivers
Problem: power handling is too low. I'd like 100 RMS to match my mains and center. Unfortunately, this design calls for a 30RMS woofer and 50RMS tweeter. I don't know how to adjust the crossover if I change the drivers to higher-power ones.

In general, is it enough to match just the freq of the crossover? Can I just buy one from PartsExpress that matches the number the designer computed, or do I have to use their schematic?

Hey Struan,
I'm just about to start on a set of Audax surrounds designed by Joe D'Appolito. They have gotten very good reviews, and the electronic parts (everything but the cabinets) can be had for less than $100 per speaker.http://www.audax.com/doit/us_ht08.shtml

You can purchase the kit several places including Solen and Madisound, I believe.

I also looked at the Adire audio Kit81s, but I didn't like the cabinet design from an aesthetic point of view. Notice however that they both use the same tweeter.

I'm looking at the Audax model, and I can't find info such as power handling and impedance. I need 8ohm speakers that can handle ~100W RMS. Do you know if they'll fit that? Most of the components seem to have much lower power handling, and the drivers are 6ohm.

typically you want to have the drivers matched for front, rear and center... its not as much the crossover as it is the timbre of the speakers. the individual tone that gives each speaker its character. this may be next to impossible with what you have, but it may not sound so great if you dont match the timbre.

That's true, I probably should use matched drivers. But I didn't build my mains (Tannoy) or center (Boston Acoustics); I just bought the best speakers I could afford at the time, so I don't really know what kind of drivers are in them (I think Tannoy makes their own--does anyone know for sure?). I'm not disappointed with the quality, especially since I had a pretty small budget then.

However, I do plan to upgrade sometime later. I'll probably get some nicer Tannoys for the front (to have a matched set) and move my current mains to the back, or just get/build all 5 to match. But that's a long way off Right now I'm just trying to replace my current rears, which are some 800-year-old Sonys I got for free at a garage sale.

Not trying to sound too much like an Audax lover (I'm not!), but if you build the audax surrounds, and like them, you can build their LR and Center at a later date as an upgrade to your current gear AND THEN have a seamless match in timbre.

Another thought is if you actually need 100W RMS rears? Chances are (unless you listen at full volume) your not even close to putting 100W RMS into you fronts right now, plus typically you'd be putting even less though rear channels.

Thanks to everyone who replied...I ordered parts for the Georgia Tech model last night, using the Vifa drivers. I followed their specs, except I replaced the aluminum-dome tweeter with a silk-dome of similar specs.

My thinking on this is that I can build some decent rears for about $70 each. That's not a lot of money, and I at this point I'm not worried too much about matching. I can build a matched 5-speaker set later and use the vifas as bookshelf speakers in the bathroom or something. Plus, I'm relatively inexperienced at speaker building, so I'd rather get my mistakes out of the way on the cheap projects I work with a friend on all these, and he wants to try veneer now...plenty of room to make mistakes there!

One more question, though...does anyone know a good place to get audio inductors for crossovers? I looked through about 10 online stores and 4 local ones and can't find them except at PartsExpress, which only has them in increments of .1 mH. I need a .68 mH, so I had to buy a .7. I figure that's not _too_ bad--.68 is almost within the 2% tolerance anyway. Will that difference matter much?
So I guess I had two questions, sorry.